Over 1.1 million breast biopsies are performed each year in the United States alone. Of these, about 80% of the lesions excised during biopsy are found to be benign while about 20% of these lesions are malignant.
In the field of breast cancer, stereotactically guided and percutaneous biopsy procedures have increased in frequency as well as in accuracy as modern imaging techniques allow the physician to locate lesions with ever-increasing precision. However, for any given biopsy procedure, a subsequent examination of the biopsy site is very often desirable. There is an important need to determine the location, most notably the center, as well as the orientation and periphery of the subcutaneous cavity from which the lesion is removed.
In those cases where the lesion is found to be benign, for example, a follow-up examination of the biopsy site is often performed to ensure the absence of any suspect tissue and the proper healing of the cavity from which the tissue was removed. This is also the case where the lesion is found to be malignant and the physician is confident that all suspect tissue was removed and the tissue in the region of the perimeter of the cavity is “clean”.
In some cases, however, the physician may be concerned that the initial biopsy failed to remove a sufficient amount of the lesion. Such a lesion is colloquially referred to as a “dirty lesion” or “having a dirty margin” and requires follow-up observation of any suspect tissue growth in the surrounding marginal area of the initial biopsy site. Thus, a re-excision of the original biopsy site must often be performed. In such a case, the perimeter of the cavity must be identified since the cavity may contain cancerous cells. Moreover, the site of the re-excised procedure itself requires follow-up examination, providing further impetus for accurate identification of the location of the re-excised site. Therefore, a new marker may be placed after re-excision.
While biopsy markers are well known, examples of improved biopsy markers are described in U.S. Pat. No. 6,356,782, entitled “SUBCUTANEOUS CAVITY MARKING DEVICE AND METHOD” and U.S. Pat. No. 6,371,904, entitled “SUBCUTANEOUS CAVITY MARKING DEVICE AND METHOD” each of which is incorporated by reference herein. Placement of such biopsy markers may occur through either invasive surgical excision of the biopsy, or minimally invasive procedures such as fine needle aspiration or vacuum assisted biopsy.
In a fine needle aspiration biopsy, a small sample of cells is drawn by a thin needle from the lump or area of suspect tissue. If the suspect area or lump cannot be easily felt, non-invasive imaging may be used to help the doctor guide the needle into the right area. A core biopsy is similar to a fine needle aspiration biopsy, except that a larger needle is used. Under a local anaesthetic, the doctor makes a very small incision in the patient's skin and removes several narrow sections of tissue from the suspect area of tissue through the same incision. The core biopsy provides a breast tissue sample rather than just individual cells. Thus making it easier for the pathologist to identify any abnormalities.
Vacuum-assisted biopsy is performed through the skin and may rely upon ultrasound or stereotactic guidance to determine the location of a suspect area of tissue. Two commonly used vacuum-assisted breast biopsy systems are Mammotome® supplied by Johnson & Johnson Ethicon Endo-surgery or MIBB® supplied by Tyco International. Examples of such devices may be found in U.S. Pat. No. 5,526,822 entitled “Methods and Apparatus for Automated Biopsy and Collection of Soft Tissue,” U.S. Pat. No. 5,649,547 entitled “Methods and Devices for Automated Biopsy and Collection,” U.S. Pat. No. 6,142,955 entitled “Biopsy Apparatus and Method” and U.S. Pat. No. 6,019,733 entitled “Biopsy Apparatus and Method” the entirety of each of which is incorporated by reference herein. Such breast biopsy systems include a probe that is inserted through the skin and is usually adapted to provide a vacuum to assist in obtaining the biopsy sample.
FIGS. 1A-1D illustrate an exemplary biopsy probe 10. As illustrated, the distal ends of probes 10 of these biopsy systems are adapted to both penetrate tissue and to contain a cutting member 12 which facilitates the removal of the biopsy sample. The cutting member 12 will contain an aperture 14 (often referred to as a “probe window.”) The aperture 14 may be located on a side of a probe 10.
Once inserted through the skin, the cutting member 12 of the probe 10 aligns with suspect tissue 1 via stereotactic, ultrasound, or other means. After proper positioning of the probe 10, a vacuum draws the breast tissue 1 through the probe aperture 14 into the probe 10. As illustrated in FIG. 1B, once the tissue 1 is in the probe 10, the cutting member 12 actuates to capture a tissue sample 3. The tissue sample 3 may then be retrieved through the probe 10 to a tissue collection area (e.g., a standard pathology tissue cassette). FIG. 1C illustrates the probe 10 after the tissue sample is cleared from the aperture 14. Note that the illustration depicts a portion of the cutting member 12 as being retracted, leaving aperture 14 open; the cutting member 12 may alternatively be placed in a closed position during retrieval of the tissue sample.
The biopsy system is often adapted such that the cutting member 12 and aperture 14 rotate (e.g., via manipulation of a thumbwheel on the probe or biopsy system) with respect to the biopsy system. After excision of a tissue sample from the area of suspect tissue, the radiologist or surgeon may rotate the probe 10 and the aperture 14 to a new position relative to the biopsy system. FIG. 1D illustrates the probe 10 and aperture 14 after being rotated but without being removed from the body. The rotation of the probe 10 and aperture 14 permits excision of multiple subsequent biopsy samples from a target area of suspect tissue with only a single insertion of the biopsy probe 10. It should be noted that FIG. 1D is provided merely to illustrate the rotation of the probe 10 within the body. As such, the placement of biopsy markers is not illustrated in the figure. Moreover, the cutting member 12 is depicted in a closed position. This may ease rotation of the probe 10 within the tissue.
The entire cycle may be repeated until sampling of all desired areas occurs (typically, 8 to 30 samples of breast tissue are taken up to 360 degrees around the suspect area). Accordingly, it is important that the operator of the biopsy system is able to identify the orientation of the probe aperture 14 relative to the biopsy system at any given time while the probe aperture 14 remains within the tissue. Often, demarcations on the thumbwheel permit the identification of the probe orientation.
The above described removal of tissue samples creates tissue cavities. Hence, for reasons that are apparent to those familiar with such biopsy procedures, placement of a biopsy marker through the probe is most desirable. For example, repeated removal of the probe and insertion of a biopsy marking device may cause unneeded additional discomfort to the patient undergoing the procedure; removal of the probe may introduce error in placement of the biopsy marker into the desired location; repeated removal and insertion of each of the devices may prolong the duration of the procedure or spread cancer cells; after the probe removes a tissue sample, it is in the optimal location to deposit a marker; etc.
Biopsies may be performed with other tissue sampling devices as described in U.S. Pat. Nos.: U.S. Pat. Nos. 4,699,154; 4,944,308, and 4,953,558 the entirety of each of which is incorporated by reference herein. Such devices obtain a biopsy sample through a hollow biopsy needle having an aperture located in a distal end of the biopsy needle. As with the biopsy devices previously described, once the tissue sampling devices removes tissue and creates a biopsy cavity, it may be desirable to place a marker in the area of the biopsy cavity.
In view of the above, there remains a need for an improved biopsy marker delivery system that may facilitate placement of a biopsy marker and also may be used with commercially available biopsy systems.